The crew exhibited signs of “forgetfulness, confusion and inability to think straight” as well as nausea, headaches and dizziness, an internal airline report read.

In both cases the airlines found no fault with their planes.

The Aerotoxic Association — a watchddog group founded and run mostly by former airline pilots and attendants — claim 96 percent of “fume events” go unreported. It estimates 360 incidents occur each day in the US and 1,300 worldwide.

Experts differ wildly on the frequency of such events which, according to the flight attendants union manual, are usually caused when oil or hydraulic fluid leaks onto hot engine compressors, releasing fumes that can leak into the cabin through old or faulty seals.

A 2015 study by Kansas State University claims fumes seep into cabin air about 5.5 times a day on U.S.-based flights.

According to the Federal Aviation Administration, “the events are rare,” with 900 reported incidents over the last 10 years — much fewer than one a day.

“It just goes to show you how there’s such a massive discrepancy between what’s getting officially recorded and what’s not,” said John Hoyte, an English pilot who founded Aerotoxic Association in 2007. He claims his group’s estimates come from internal reports obtained through sources.

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Hoyte said he had to quit his job with a regional carrier because “I felt like a zombie and like I was constantly intoxicated,” he said. “I had very bad memory problems, difficulty processing thoughts and terrible fatigue.”

The FAA only requires airlines to report fume events if the cause is a confirmed mechanical failure, said Judith Anderson, a health and safety specialist with the Association of Flight Attendants. Fumes from leaking oil wouldn’t necessarily be reported.

“Nobody is really keeping track of this — or at least not close track,” said Anderson. “We know this is happening and we see a consistent pattern of symptoms, but people don’t make the connection that toxic fumes are making them sick.”

In April 2016, former Alaska Airlines flight attendant Vashti Escobedo sued Boeing after allegedly developing a stutter, a right-hand tremor and memory loss. She blames “contaminated cabin air” on an August 2015 flight from Seattle to Austin, TX, for making her “extremely disoriented” and ending her career, according to legal papers.

Jet engine oil contains an aromatic compound called tricresyl phosphate, which first developed for chemical warfare, according to published reports and advocates. It’s added to the engine oil as an anti-wear agent, necessary because of the extremely high temperature jet engines reach. When inhaled, such organophospates attack and kill brain cells.

The FAA maintains that “studies have indicated that cabin air is as good as or better than the air found in offices and homes,” and that “the cabin environment in the vast majority of commercial flights is safe,” a spokeswoman said.